The present invention relates to a recording and reproducing apparatus, specifically to a magneto-optical (MO) disk drive having a laser beam splitter for splitting a laser beam, and used for reading and writing optically encoded data.
Conventional beam splitters are built with the external optical surfaces perpendicular to entering and exiting light beams. Hence, stray light from a laser source that impinges on an optical surface can be reflected directly back along an intended optical path. Since semiconductor lasers used in optical data reading are sensitive to feedback, it is not favorable to allow laser light to re-enter the semiconductor laser along its exit path. Furthermore, a reflected laser beam from a data-bearing optical medium, carrying a signal representative of the data borne, should be as free of surface-induced noise from a beam splitter as possible.